Research On Control Method Of Switched Nonlinear System With Actuator Dead Zone

Because the actuators are always accompanied by dead zone,they are affected by the actual action of the components.In the production process,with the change of working conditions and environment,the parameters of the actuator also change.In addition,parameter changes over time can cause steady state errors in the control system,which can limit control performance.However,many studies fail to consider the switching characteristics of actual systems.The major reasons are as follows: In a switching system,there are many switching rules.And under some conservative conditions,the system is stable and there exists no uniform switching signal,which can make the stability analysis of the system very complicated.Furthermore,it is difficult to employ Lyapunov function to analyze the stability of the system because of the jump of dead-zone parameters.The design of existing adaptive control schemes includes controller design based on Lyapunov analysis and parameter adaptive law design.However,the non-derivable Lyapunov function makes it impossible to design the controller by this method.Therefore,in this study,The aim is to realize the tracking control of a switched nonlinear system with dead zone.To handle the above issues,this paper studies the adaptive tracking control for nonlinear systems with actuator dead zone.The major work of the study includes the following situations:(1)An adaptive fuzzy control scheme is presented for nonlinear systems with uncertain dead zone.Fuzzy logic systems can be utilized to approximate unknown functions.To estimate the unpredictable state,a switch fuzzy state observer is constructed.A variety of Lyapunov functions and fuzzy methods are proposed to provide fuzzy controllers to ensure the boundary and ideal tracking performance of the closed-loop system.(2)Adaptive Tracking Control for Unknown Dead Zone Switched Systems,nonconstant control gain and asymmetric full state constraints is studied.Aiming at the nonlinear problem of unknown input dead-zone of unknown nonconstant control gain function,a smooth dead-zone inverse algorithm is used in fuzzy logic system.For switching systems with unknown dead zones and full state constraints,it is difficult to design a controller based on Barrier Lyapunov Function.In addition,the presented controller can prevent the violation of the constrained states,and guarantee the boundedness of the closed-loop system.(3)Uncertain dead-zone compensation has important theoretical and practical significance in adaptive fuzzy fixed time control of switched systems.Due to the complex switching framework and the existence of dead zone input,it is difficult to construct a fixed time controller,there is no report about this issue.Using a power integrator method and a fuzzy dead zone model,a fuzzy timing controller is proposed to solve the above problems.The stability of the closed loop system in a certain period of time is proven.